The present invention relates to pigment materials and their use in coating compositions.
Pigment materials such as calcium carbonate and calcined kaolin are employed together with hydrophilic binders such as acrylic and styrene butadiene latices and optionally other ingredients in compositions to coat paper and like materials to provide amongst other things smooth or gloss surfaces which can be printed upon.
Such printing may be carried out using an electrophotographic printer. Dry toner particles providing print information are applied to the coated paper surface by a fuser of a fuser station of such a printer. The toner particles incorporate a thermo-softening polymer and the fuser causes the polymer partially to melt and thereby causes the toner particles to adhere to the surface to be printed. The binders employed in coating compositions may have a relatively low glass transition temperature, eg less than 40.degree. C., and the heat applied by the fuser can cause the binder of the coating composition providing the surface to be printed upon to become soft and sticky. The heat applied may be sufficient that when the printed sheets are stacked or reeled into multiple layers adjacent sheets or layers may adhere together. This can cause later paper handling and/or feeding problems which are of concern to the paper printer.